The present disclosure relates to a transverse electric field type liquid crystal display panel, and more particularly, to a transverse electric field type liquid crystal display panel with a high aperture ratio, in which a shape of a sub-pixel has a curved portion and an end portion of a display area is rectangular.
Liquid crystal display panels have the characteristics of being light weight, thin, and having low power consumption as compared with CRTs (cathode ray tubes), and thus are used in various electronic apparatuses as displays. Through the use of a rubbing-processed alignment film, a liquid crystal display panel changes the direction of liquid crystal molecules arranged in a predetermined direction by an electric field, thereby changing a transmittance ratio or a reflectance ratio of light to display an image.
As a method of applying an electric field to a liquid crystal layer of the liquid crystal display panel, there are a longitudinal electric field manner and a transverse electric field manner. In the longitudinal electric field type liquid crystal display panel, a substantially longitudinal electric field is applied to liquid crystal molecules by a pair of electrodes disposed with a liquid crystal layer interposed therebetween. As the longitudinal electric field type liquid crystal display panel, a TN (Twisted Nematic) mode, a VA (Vertical Alignment) mode, an MVA (Multi-domain Vertical Alignment) mode and the like are known. In the transverse electrical field type liquid crystal display panel, a pair of electrodes insulated from each other are provided on the inside of one of a pair of substrates disposed with a liquid crystal layer interposed therebetween, and a substantially transverse electric field is applied to the liquid crystal molecules. As the transverse electric field type liquid crystal display panel, one of an IPS (In-Plane Switching) mode in which a pair of electrodes are not overlapped in the plan view, and one of an FFS (Fringe Field Switching) mode in which a pair of electrodes are overlapped are known.
In the IPS mode liquid crystal display panel, a pair of electrodes, such as a pixel electrode and a common electrode, is formed in a tooth shape to engage with each other in a state of electrical insulation, and a transverse electric field is applied to the liquid crystal between the pixel electrode and the common electrode. The IPS mode liquid crystal display device has an advantage of a wide view angle wider than that of the longitudinal electric field type liquid crystal display device.
In the FFS mode liquid crystal display panel, a pair of electrodes such as an upper electrode and a lower electrode are provided on layers different from each other with an insulating film interposed therebetween, a slit-shaped aperture is provided in the upper electrode, and a substantially transverse electric field passing through the slit-shaped aperture is applied to a liquid crystal layer. Since the FFS mode liquid crystal display panel is capable of obtaining a wide view angle and has an effect whereby image contrast is capable of being improved, recently, it has come into widespread use.
In the transverse electric field type liquid crystal display panel, the slit-shaped aperture (case of FFS mode) formed in the upper electrode or an aperture (case of IPS mode, hereinafter, also referred to as “slit-shaped aperture”) formed between both electrodes in the plan view extends to be slightly inclined with respect to a rubbing direction, to enable rotation of the liquid crystal molecules in the same direction. In a color display liquid crystal display panel, it is possible to reduce the change of color caused by the view angle, by a multi-domain process of dividing the inclination angle with respect to the rubbing direction of the slit-shaped aperture into two positive and negative areas. However, since it is difficult to form an electric field in a desired direction at an end portion of the slit-shaped aperture, when the slit-shaped apertures in the extending directions different from each other are separated, the number of end portions of the slit-shaped apertures increases and as a result the aperture ratio is lowered.
In a liquid crystal display panel disclosed in Japanese Unexamined Patent Application Publication No. 2002-014374 or Japanese Unexamined Patent Application Publication No. 2008-083386, a slit-shaped aperture is provided with a curved portion, the multi-domain process is achieved and the aperture ratio is increased by connecting slit-shaped apertures extending in different directions.